<form name="loginForm" id="loginForm" action="https://cas.baidu.com/?action=login" method="post" target="frame_url">
      <input type="hidden" name="appid" value="${appid}">
      <input type="hidden" name="selfu" value="${selfu}">
      <input type="hidden" name="fromu" value="${fromu}">
      <input type="hidden" id="sid" name="sid" value="${sid}">
      <input type="hidden" id="pwd" name="pwd" value="${pwd}">
      <input type="hidden" id="entered_login" name="entered_login" value="${entered_login}">
      <input type="hidden" id="entered_password" name="entered_password" value="${entered_password}">
      <input type="hidden" id="entered_imagecode" name="entered_imagecode" value="${entered_imagecode}">
</form>
<iframe id="frame_url" name="frame_url" style="width: 100%;height: 100%;"></iframe>
<script language="javascript">
   document.getElementById("loginForm").submit();
</script>